"Btrfs holds the promise of giving Linux many enterprise class file system features similar to ZFS but with even more features and better performance. In fact, many Linux experts think that btrfs is one of the keys to the future of Linux. While btrfs is not quite ready to be your only file system, it is in the kernel ready for testing and is still undergoing very heavy development. In this article we will introduce the key features of btrfs find out how it compares to existing file systems."

I doubt whether Oracle have given it any thought at all. The people who will end up making the decisions probably won't even know what ZFS is. However, by buying Sun Oracle have committed themselves to supporting Solaris and ZFS for those who are using it, despite its decline over the past decade, so it'll be around for some time yet. Just as people aren't going to reformat everything to get ZFS, those using ZFS aren't going to reformat everything when btrfs comes along.